Glossary

Confirmation test

A second-stage analysis that confirms (or rejects) an initial non-negative screening result.

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In workplace drug testing, an initial non-negative immunoassay screen is always followed by a confirmation test — typically GC-MS or LC-MS/MS — at a SAMHSA-certified laboratory before any result is reported as a positive. Confirmation testing rules out the false positives common to immunoassay.

Related terms & pages

Glossary

Immunoassay

The initial screening method that uses antibodies to detect drug classes — fast but less specific than confirmation.

 Glossary

GC-MS (gas chromatography–mass spectrometry)

A confirmation method that separates and identifies individual analytes by mass-to-charge ratio.

 Glossary

LC-MS/MS (liquid chromatography–tandem mass spectrometry)

A confirmation method that uses two stages of mass analysis, often used for fentanyl and other low-cutoff analytes.

 Glossary

Medical Review Officer (MRO)

A licensed physician trained to interpret drug-test results and serve as the medical buffer between the laboratory and the employer.